Patent GB-601527-A (GB)
Abstract: 601,527. Change computing and delivering cash registers. WATSON, K. L. Aug. 23, 1946, No. 19177/45. [Class 27] Change computing and delivering mechanism incorporated in a cash register comprises a differential unit with two input members, one moved by the operation of the price keys according to the purchase price and the other according to the amount received, the output member of the differential, which is driven differentially by the two input members, controlling changeselecting contacts according to its final position so that change appropriate to the transaction is automatically delivered. The amount received may be set up by a second set of keys similar to the price keys, but in the particular apparatus shown, the coins are inserted into the apparatus and operate the receipt input member automatically. The differential unit comprises bevel sun-wheels E, F adapted to be reversely rotated according to the price and tender amounts, and planet pinions in a cage G which controls the issue of change. Figs. 5 and 6 (not shown) show the arrangement for the pence section; there are similarly arranged sections for pounds, shillings and farthings. Sun-wheel E is connected to a shaft E3 arranged for stepwise rotation by pawl and ratchet mechanisms E4 each operable by a magnet E1d-E6d which are selectively energised, one or more at a time, by operation of a price key. Those keys which energise more than one magnet are arranged to close the magnet contacts concerned in succession, so that the total rotation of sun-wheel E is commensurate with the sale amount. Sunwheel F is geared to a shaft F3 similarly operable by magnets F1d, F3d and F6d selectively energised by contacts operated by the paid in coins themselves. The planet cage G, which finally assumes a position corresponding to the change due in the pence section, has an arm G1 arranged to actuate a series of contacts M1-M11 appropriately connected to the changeissuing control magnets M1d-M6d. If the change thus determined is negative, and arm G1 lies to the right (Fig. 5, not shown) of the normal shown, it bridges contact strips G4, G5 which deduct 1 unit from the shillings section, and a second arm G2opposite G1 effects delivery of pence change equal to one shilling less the negative amount. The deduction from the shillings section is effected by means similar to that shown in Figs. 5 and 6 for deducting 1d from the pence section when the farthings section is in debit. Thus the contact arms G1, G2 are maintained in a normal angular position relative to the cage G by a magnet G8 energised by engagement of a bridging contact (similar to G3) on the farthings contact arm with contact strips (similar to G4, G6) as long as that arm is not in debit. When it is, the circuit of G8 is broken, and that of a second magnet G7 is made through further contact strips (similar to G4, G5), and this rocks the arm G1, G2 backwards one step to make the deduction. When the pounds section is in debit the change bar is locked to prevent any change being obtained. To provide for transfer between each section and the next higher, both as regards price and tender, gears E2, F2 on the shafts E3, F3 have contact fingers T9 spaced there around and which, in the case of the pence section shown, close contacts to add or subtract one unit in the shillings section each time twelve units have been passed into either side of the pence section. The wheels E2, F2 do not drive the differential directly, pinions T3 driven by them being loose on the shafts E1, F1 of the differential. When the change bar is depressed, magnets are energised to project pawls T5 on discs T4 fast with the pinions into the path of pins T8 on arms T7 secured to the differential shafts. The planet cage G is then turned back, e.g. through frictional mechanism, until the pins T8 abut the pawls, and this takes account of the remaining pence in the pence section. The apparatus has individual assistant keys which have to be operated in addition to the change bar, and these keys have contacts serving to energise magnets T11 to release holding pawls for the ratchet drives enabling the whole mechanism to be zeroised by springs. Other contacts on the assistant keys bring into action individual totalising registers for the individual assistants. A change-over switch enables price values to be subtracted by bringing oppositely-acting ratchet devices E4 into action. Coin action, electrical connection and multiple coin; coin discharging mechanism. The coins inserted at L, Fig. 12, (not shown), are passed singly, by an agitator L2, to a narrow chute L<1>, each coming to rest between the appropriate pair of a series of contacts L3 of progressively decreasing separation. The coin closes the circuit between the contact pair to energise the corresponding magnet, e.g. E1d-E6d. A magnet L4 opposite the coin is simultaneously energised to effect immediate discharge of the coin.